Tools for stamping concrete and similar materials have been employed for many years. Such tools have frequently been platform tools designed to be utilized in conjunction with a plurality of similar tools and operated by workmen walking on the platform and tamping the tool into the surface of the concrete using a striking driver. The platform tools incorporate penetrating blades arranged in patterns to simulate bricks, tiles and other conventional materials. To mate between adjacent tools and patterns, at least one of the blades normally parallels the edge of the platform thus forming a closed end of the tool. Since the blades are generally tapered toward the tip, then the closed end of the tool makes a slopting impression in the hardening concrete. The ends of the blades terminating opposite the closed end terminate in a vertical surface. Accordingly, when an adjacent tool is layed up against the platform of a first tool, a sloping surface-to-vertical surface mating relationship is produced, leaving a gap or void which fills with hardening concrete. This concrete must be worked out by hand tools. The hand tool or "tinkering" operation, as it is known, considerably slows the production of imprinted concrete and increases the cost thereof.
In one prior art tool, as is described in more detail in U.S. Pat. No. 3,406,618, the problem was addressed by providing fillets on the closed face of the tool. However, these fillets are susceptible to damage in use, and are difficult to align with the corresponding blades on an adjacent tool. As a result, the use of this tool slows production.
Therefore, it is desirable to have a tool for making impressions in hardenable materials that eliminates the need for hand tool operations at the closed end-open end interface between adjacent tools and doesn't slow production. Such a tool is particularly desirable where it does not reduce the overall integrity of the resulting tool or substantially increase its manufacturing cost.